1. Field of the Invention
The invention relates to an electronic apparatus with a printer such as an electronic portable calculator.
2. Related Background Art
As an example of conventional electronic apparatuses with printers, an electronic portable calculator (hereinafter, simply referred to as a "calculator") will now be described hereinbelow. The calculator has a printer of a predetermined printing speed according to the type of apparatus. The printer prints in accordance with a key operation, particularly, an operation of a function key such as addition "+", subtraction "-", multiplication ".times.", division ".div.", sign of equality "=", or the like. For example, a full-scale office calculator that is used in a bank, company, office, or the like is equipped with a relatively high speed printer having a printing speed of3.8 l/sec or 5 l/sec. On the other hand, a portable calculator is equipped with a relatively low speed printer having a printing speed of 2 l/sec or 3 l/sec. Therefore, the user who desires a high speed printing process as in bank business affairs generally purchases a calculator with a high speed printer having a printing speed such as 5 l/sec. The general user who does not need a high speed printing process ordinarily purchases a calculator with a low speed printer having a printing speed such as 2 l/sec.
Conventional apparatuses equipped with printers have the following problems because the printer have different printing speeds.
Generally, there is a proportional relation between the printing speed of the printer and the noises generated upon printing. As the printing speed rises, the noises generated upon printing increase.
There is likewise a proportional relation between the printing speed and the electric power consumption. As the printing speed rises, the electric power consumption increases.
Therefore, when different printing speeds are installed on a calculator, and the printing speed is fixed to a predetermined speed as mentioned above, even when a user slowly operates a key, the printer always prints at a high speed. Such is the case for full-scale office calculators used in a bank, company, office, or the like. There are consequently problems such that the noises which are generated upon printing are large and the electric power consumption also increases. On the other hand, in case of the portable calculator, when the user becomes experienced in the key operation and the key operating speed rises, there is a problem such that the low speed printer cannot keep up with the key operation of the user.
To solve such problems, apparatuses such that the printing speed (printing mode) is changed in accordance with the key operating speed of the user have already been proposed. For instance, there are an apparatus such that the printing speed is changed in accordance with an input speed of a key (Japanese Patent Application Laid-open No. 5-181805), an apparatus such that the printing speed is changed in accordance with an amount of key buffer (Japanese Patent Application Laid-open No. 5-342165), and an apparatus such that the printing speed is changed in accordance with an amount of key buffer during the printing process (Japanese Patent Application No. 5-139992, which corresponds to Japanese Patent Application Laid-Open No. 6-332863). According to those apparatuses, the printing speed is raised when it is necessary to print at a high speed.
However, in the above conventional electronic apparatuses with printers, fundamentally, the printing speed is set to a high speed for a high speed key operation and to a low speed for a low speed key operation. Therefore, there is a problem such that in case of a slow key operation, although a fast key operation cannot be performed, the user wants to quickly see the print result (for example, in case of the printing of the result of a calculation), the printing speed is not necessarily high enough.